Horizontal Symmetry: Bottom Up and Top Down
arXiv:1105.5166
Abstract
A group-theoretical connection between horizontal symmetry $\G$ and fermion mixing is established, and applied to neutrino mixing. The group-theoretical approach is consistent with a dynamical theory based on $U(1)\times \G$, but the dynamical theory can be used to pick out the most stable mixing that purely group-theoretical considerations cannot. A symmetry common to leptons and quarks is also discussed. This higher symmetry picks over to be the preferred symmetry for leptons.
Based on a talk given at WIN 11, Jan 31 to Feb 5, 2011, Capetown, South Africa